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- Title
Microvascular blood flow responses to muscle contraction are not altered by high-fat feeding in rats.
- Authors
St-Pierre, P.; Keith, L. J.; Richards, S. M.; Rattigan, S.; Keske, M. A.
- Abstract
Aim: Exercise and insulin each increase microvascular blood flow and enhance glucose disposal in skeletal muscle. We have reported that insulin-mediated microvascular recruitment in a diet-induced model of insulin resistance (high-fat feeding for 4 weeks) is markedly impaired; however, the effect of muscle contraction in this model has not been previously explored. Methods: We fed rats either normal (ND, 10% calories from fat) or high-fat (HFD, 60% calories from fat) diets ad libitum for 4-8 weeks. Animals were then anaesthetized and one hindlimb electrically stimulated to contract at 0.05, 0.1 and 2 Hz (field stimulation, 30 V, 0.1 ms duration) in 15 min stepwise increments. Femoral artery blood flow (Transonic flow probe), muscle microvascular blood flow (hindleg metabolism of 1-methylxanthine and contrast-enhanced ultrasound) and muscle glucose disposal (uptake of radiolabelled 2-deoxy- d-glucose and hindleg glucose disappearance) were measured. Results: Both ND and HFD rats received the same voltage across the leg and consequently developed the same muscle tension. Femoral artery blood flow in the contracting leg increased during 2 Hz contraction, but not during the lower frequencies and these effects were similar between ND and HFD rats. Muscle microvascular blood flow significantly increased in a contraction frequency-dependent manner, and preceded increases in total limb blood flow and these effects were similar between ND and HFD rats. Muscle glucose disposal was markedly elevated during 2 Hz contraction and was comparable between ND and HFD rats. Conclusion: Contraction-mediated muscle microvascular recruitment and glucose uptake are not impaired in the HFD insulin resistant rat.
- Subjects
MICROCIRCULATION disorders; MUSCLE contraction; BLOOD flow; HIGH-fat diet; INSULIN resistance; METHYLXANTHINES
- Publication
Diabetes, Obesity & Metabolism, 2012, Vol 14, Issue 8, p753
- ISSN
1462-8902
- Publication type
Article
- DOI
10.1111/j.1463-1326.2012.01598.x